Railway rail handling apparatus

ABSTRACT

Apparatus for handling lengths of railway rail by advancing such rail longitudinally wherein opposed rail gripping wheels define a nip through which a rail is to be advanced and are movable one relative to the other by gripping force means and in accommodation of rail flexure for assuring that tractive force is exerted on a rail when the wheels are driven in rotation by a drive means operatively connected thereto.

United States Patent John E. Moorefield Charlotte, N.C.;

Charles H. Moorefield, executor 751,191

Aug. 8, 1968 Jan. 26, 1971 lnventors Appl. No. Filed Patented RAILWAY RAIL HANDLING APPARATUS 10 Claims, 6 Drawing Figs.

US. Cl.; [04/2 Int. Cl EOlb 29/02 Field of Search 104/1, 2, 3, 4, 5, 6

References Cited UNITED STATES PATENTS 4/1937 Breaker 104/5 3,199,462 8/1965 Hooker 3,286,648 11/1966 Brosnan Primary Examiner-Arthur L. LaPoint Assistant Examiner-Richard A Bertsch Att0rney-Parr0tt, Bell, Seltzer, Park & Gibson ABSTRACT: Apparatus for handling lengths of railway rail by advancing such rail longitudinally wherein opposed rail gripping wheels define a nip through which a rail is to be advanced and are movable one relative to the other by gripping force means and in accommodation of rail flexure for assuring that tractive force is exerted on a rail when the wheels are driven in rotation by a drive means operatively connected thereto.

PATENTED JAN26 IQYI SHEET 1 BF 4 PATENTED JAN 26 IBYI SHEET 3 UF 4 INVENTORI JOHN E. MomaeHELb lllllll'lllll f ATTORNEYS RAILWAY RAIL HANDLING APPARATUS In recent years, it has become a common practice for a railway to employ continuous or long length rail sections. In contrast to the rail lengths used previously, which were on occasion as short as feet, the continuous or long length sections now finding favor with railroads are as much as a quarter of a mile or more in length. Due to the substantial length and weight of railway rail when formed into continuous lengths of this type, special handling problems have been encountered and it has been necessary to provide special equipment for handling the lengths of rail, as the rail cannot be effectively handled manually. One particular environment in which the necessity for such rail handling apparatus becomes quite clear is in the laying of lengths of rail onto a roadbed for installation, or in the taking up of lengths of rail for maintenance.

Heretofore, the apparatus which has been most widely used for handling lengths of railway rail is an apparatus which may be characterized as an endless track machine. That is, a pair of endless tracks somewhat similar to those employed in tracklaying vehicles such as bulldozers and the like are each supported on rollers or other guides for movement along predetermined paths, including reaches substantially parallel and opposed to each other, in order to grip the upper and lower surfaces of a rail to be handled. Due to this arrangement for the paths, the supporting structure chosen for guiding the tracks is substantially fixed or rigid during the use of the apparatus, providing only such capability for adjustment as is required to position the parallel reaches of the track at a spaced distance corresponding to the height of the rail to be advanced. The transfer of tractive force from the endless track members, to which such effort is applied from a suitable motive force means, to the rail being handled thereby is thus dependent primarily upon the large area of contact between the endless track members and the rail, with the force normal to the area of contact being determined by the rigid spacing "of the tracks.

As such endless track rail handling apparatus has come into use in the railroad industry, certain difficulties with such apparatus have been encountered. One of the major difficulties encountered is in maintenance, due to the manner in which the endless track members must necessarily be constructed. More specifically, it is necessary that the endless track members be assembled as an articulated series of individual links or plates, in order to permit guiding the track members along the necessary closed path of travel. As a result of the articulation of each individual link, there are a large number of points of engagement which will wear, and accordingly, a large number of points of potential failure of the track member. In the event that the track member should fail by parting at one of the points of articulation, it is then necessary to carefully advance the track to a location along the closed path of travel at which the parted links are available for replacement of the articulation means. This must be accomplished without disturbing the spacing of the adjacent links to be rejoined to-such an extent to require completely rethreading the track on the supporting rollers.

Other difi'lculties which have been encountered in the use of such endless track rail handling apparatus have been slippage of rails relative to the endless track members and jamming or accelerated wear of the endless track members when an attempt is made to prevent such slippage. Specifically, in the endless track rail handling apparatus which has been employed heretofore, great care must be exercised in adjusting the relative positions of the parallel opposed reaches of the track member paths in order to assure that the force of engagement normal to the track members and the rail to be handled is sufficient to assure frictional transmission of tractive force, without pinching the rail so tightly as to damage the rail handling apparatus. In addition to the effect of this adjustment on the frictional force which is required for the transmission of tractive force, any bowing or flexure of the rail being handled, such as will result in feeding the rail to and from rail storage cars, cannot be accommodated by the rigid mounting of the guide rollers for the track members and causes wide l'luctua' tion in the forces applied to the rail handling apparatus.

One expedient which has long been used in the railway industry inorder to assure that adequate traction is obtained between a locomotive wheel and a slippery rail has been the use of sand, blown onto the surface of the track adjacent the contact point between the track and the locomotive wheel. Where attempts are made to adopt this expedient for use with endless track rail handling apparatus, to overcome slippage resulting from a reduction in the friction force as mentioned above, the apparatus is damaged at least to the extent of greatly increased wear rates, and upon occasion becomes jammed and entirely inoperative due to the entrance of the sand into certain of the operating parts of the apparatus.

With the above discussion in mind, it is an object of my invention to provide an apparatus for handling lengths of railway rail by advancing the rail longitudinally wherein the difficulties and deficiencies of previously used rail handling ap paratus are obviated. In realizing this object of my invention, I provide an apparatus in which transmission of tractive force through a rail engaging means to the rail, to advance rail longitudinally, is assured by the provision of means for controlling the friction force of engagement between the rail gripping means and the rail being advanced and means for accommodating rail flexure without reducing the friction force.

A more specific object of my invention is to provide an apparatus, of the general type described above, wherein feed wheel means including opposed feed wheels define therebetween a nip for receiving a rail to be advanced and are driven in rotation by motive force means operatively connected to the feed wheels. In accordance with my invention, a gripping force means is operatively connected to the feed wheel means for applying a force moving the wheels together and into tightly gripping engagement with a rail disposed in the nip therebetween, so that the exertion of tractive force on the rail by the feed wheel means is facilitated.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which;

FIG. 1 is a plan view of the apparatus of my invention, as applied to a rail handling train;

FIG. 2 is an elevation view of the rail'handling train of FIG.

FIG. 3 is a view similar to FIG. I of a rail handling car included in the rail handling train, the car having mounted thereon two of the rail handling apparatus of my invention;

FIG. 4 is an end elevation view, in partial section, through one of the apparatus mounted on the rail handling car of FIGS. I through 3, taken substantially along the line 4-4 in FIG. 2;

FIG. 5 is a side elevation view, in partial section, of the rail handling apparatus of FIG. 4, taken substantially along the line 5-5 in FIG. 4; and

FIG. 6 is a schematic illustration of a hydraulic fluid circuit suitable for providing control over the elements of the apparatus of FIGS. 4 and 5.

Referring now more particularly to the drawings, my apparatus 20 for handling lengths of railway rail by advancing the rail longitudinally is there illustrated as mounted upon a rail handling car 11 for use in a rail handling train 10. It is to be understood at the outset, however, that the rail handling apparatus 20 need not be mounted upon a rail handling car such as the car 11 or included within a rail handling train such as the train 10. Instead, the apparatus 20 may be mounted in a fixed position, as in a rail maintenance shop, and employed in that fixed position for advancing rails in a manner to be described. In the particular environment shown, wherein the rail handling apparatus 20 is mounted upon a rail handling car 11, the car 11 may be assembled-with rail storage cars 12 and rail guiding cars 14 and 15 as part of the rail handling train 10. Such trains are now in use within the railway industry in laying and taking up continuous lengths of rail as described heretofore.

In order to support the operating elements of the apparatus of my invention, the apparatus includes a main frame means including end standards 21, 22, 23 and 24, secured to horizontally extending base frame members 25 and 26 to extend vertically upwardly therefrom and braced by appropriate diagonal bracing. The standards 21 and 22, adjacent one end of the apparatus 20, are joined at their upper ends by a crossbeam 28, for purposes to be pointed out more fully hereinafter. v v

In order to support a tractive force means as described more fully hereinafter and to permit that means to readily accommodate rail flexure during payout or takeoff lengths ofrail, the frame means of the apparatus 20 includes first and second subframes, respectively identified as a lower subframe 20 and an upper subframe 31. The lower subframe 30 is supported by the frame base, between the main frame members 25 and 26, for pivotal movement (as indicated by the arrows in FIG. 5) about a pivotal axis defined by an axle member 32. The subframe 30 is constructed generallyas a rectangular box, and the location of the axle 32 which defines a pivotal axis about which the subframe 30 moves is preferably approximately medially of the length of the subframe.

In order to permit the application of a gripping force to a rail engaged by tractive force means of the apparatus 20, as described more fully hereinafter, the upper subframe 31 is suspended from a lever arm including upper frame side members 35 and 36 positioned generally above the corresponding base members 25 and 26. The lever members 35 and 36 are pivoted adjacent a fulcrum end thereof to standards 23 and 24, for pivotal movement relative thereto about an axis defined by an axle member 37. The opposite free-end extremity of the lever arm formed by the members 35 and 36 is operatively connected to the piston rod of an expansible chamber cylinder device 38. The cylinder device 38 connects the free end of the lever members 35 and 36 with the crossmember 28 of the main frame of the apparatus 20 and, by suitable application of operating fluid pressure to the cylinder device 38, will move the free end up and down.

The upper subframe 31 is mounted upon the lever members 35 and 36 for pivotal movement relative thereto about an axis defined by an axle member 39, in similarity to the mounting of the lower subframe 30 for pivotal movement about an axis defined by the axle 32, and as indicated by the doubleheaded arrows in FIG. 5. Also in similarity to the construction of the lower subframe 30, the upper subframe 31 is constructed as a generally rectangular boxassembly and is supported approximately medially of its length. By the movement of the upper subframe 3K with the lever members 35 and 36, the spacing between the upper and lower subframes 30 and 31 is varied, for purposes to be pointed out more fully hereinafter.

Mounted upon the upper and lower subframes 30 and 31, in order to engage the flange and traction surfaces of a rail R to be advanced by the apparatus 20, are tractive force means including lower feed wheels 40 and 41 and upper feed wheels 42 and 43. The lower wheels 40 and 41 preferably are formed with generally right-circular cylindrical external configuration, for meeting the major area of the lower surface of the flange (FIG. 4) to engage and support the rail during handling thereof. Each of the lower wheels 40 and 41 is supported on the subframe 30 by a pair of aligned journals such as the journals 45 and 46, through which supporting axles such as the axle 47 extend. Mounted on the supporting axles 47 and 50 for the lower wheels 40 and 41 are respective drive gears 51 and 52, each of which is operatively secured with its corresponding lower wheel, 41 and 40 respectively, for driving the wheel in rotation as the drive gear is driven in rotation. Positioned between the drive gears 51 and 52 is a driving pinion 54, secured to one extremity of a driving shaft 55 and thereby operatively connected with a motive force means operable for driving the lower wheels 40 and 41. Preferably, the motive force means is an expansible chamber pressure fluid operated motor 56 mounted from the subframe 30 by an appropriate bracket 58 and supplied with pressure fluid from a suitable source, as described hereinafter. Upon application of pressure fluid to the motor 56, the drive shaft 55 is driven in rotation and motive force is transmitted to the lower wheels 40 and 41 to drive the same in rotation and advance the rail R.

The upper feed wheels 42 and 43 are similarly supported by the upper subframe 31 for rotation about horizontal axes defined by supporting axles 67 and 70, extending through supportingjournals 65 and 66 and are driven in rotation by operative connection with expansible chamber fluid pressure motor 76, suspended from the upper subframe 31 by an appropriate bracket 78. Motive force is applied to the wheels 42 and 43 through a drive train including a drive gear 74 on a drive shaft 75, which meshes with driven gears 71 and 72 respectively fixed to the wheels 42 and 43. Preferably, the upper wheels 42 and 43 are configured with a right-circular cylindrical portion of appropriate width to engage the traction surface of the head of a rail R to be advanced longitudinally by the apparatus 20 (FIG. 4), and with radially outwardly extending flanges on either side of that right-circular cylindrical portion, in order to assure that the rail R is centered properly on the rail engaging and supporting surfaces of the feed wheel means of the apparatus 20.

The cooperation of the various elements of the apparatus 20, as described above, will now be clear from a discussion of the operation of the apparatus. ,More particularly, the pivotal mounting of the upper and lower subframes 31 and 30 on the main frame elements of the apparatus 20, permitting pivotal movement of the wheel means 40, 41, 42 and 43 about the axes defined by the respective axles 32 and 39, will be seen as permitting accommodation of the apparatus 20 to flexure of the rail R, while maintaining proper engagement of the feed wheels therewith. That is, should the generally horizontally ex tending position of the rail R vary, bybeing raised on one side or lowered on the other side of the apparatus 20, such rail flexure is accommodated without significant variation in the contact between the rail and the feed wheel means of the apparatus 20. Further, by the mounting of the upper subframe 31 on the lever arms 35 and 36, movable upon application of pressure to the cylinder device 38, the spacing between opposed upper and lower feed wheels, such as lower feed wheel 40 and upper feed wheel 42, may be controllably varied to forcefully grip the rail R being advanced longitudinally by the wheels. In particular, by the employment of a second-class lever, substantial force may be developed in order to assure that adequate traction is obtained between the feed wheels such as the opposed wheels 40 and 42 and the rail R.

Several subsidiary features of the apparatus 20 of my invention assure that the rail R is smoothly advanced longitudinally. More particularly, the pressure fluid circuit adapted for supplying fluid to the motive force means including the motors 56 and 76 operatively connected to the feed wheel means, preferably assures rotation of the feed wheels 40, 41, 42 and 43 at a substantially uniform linear surface speed. To accomplish this result, the pressure fluid circuit (schematically illustrated in FIG. 6) includes a flow divider means 80 interposed in the fluid flow conduits 81 and 82 respectively supplying pressure fluid to the motors 56 and 76. Flow divider means suitable for use in the illustrated circuit are widely known in the hydraulic industry, and include structures somewhat similar to positive displacement gear pumps, wherein a pair of pumps are joined by a shaft so that the rotors of the pump must necessarily rotate at the same speed. By passing the pressure fluid flow through such a flow dividing device 80, delivery of identical-flow rates of pressure fluid to the two motors 56 and 76 is assured, thereby assuring rotation of the shafts of those motors at the same speed. If desired, the flow divider means may be such as todivide the flow in a predetermined unequal manner, in order to compensate for any predetermined inequality in radii of the feed wheels driven by the respective motors or in the gear trains operatively connecting the motors with the respective feed wheels.

Preferably, in order to accommodate use of the apparatus 20 at locations remote from readily available power, the pressure fluid circuit includes a pressure fluid pump 85 driven by an appropriate prime mover 86, such as an internal combustion engine of the diesel or gasoline type. However, it is to be understood that the prime mover 86 may be replaced by an electrical motor or other suitable power means in the event that such a power means is available due to the positioning of the apparatus 20 at a fixed location. Further, the pressure fluid motors 56 and 76 may be directly replaced by electrical motors if so desired. In operation, the pump 85 driven by the prime mover 86 circulates hydraulic pressure fluid from a reservoir 88 through conduits including the conduits 81 and 82 supplying the motors 56 and 76. Additionally, pressure fluid derived from the pump 85 is applied to the cylinder device 38 in order to provide the gripping force applied between the opposed pair of feed wheels. A rail R may be threaded into the nip between the opposed pairs of feed wheels either by hand or by the use of an auxiliary handling device such as a cable winch W (H6. 2). Thereafter, the application of hydraulic fluid pressure to the motors 56 and 76 to drive the feed wheel means in rotation ,will result in advancing the rail longitudinally.

Due to the simplicity of the tractive force means employed in the apparatus 20, the widely known expedient of sanding the rail R has proved to be adaptable in obtaining desired traction between the feed wheels and the rail R. Accordingly, should it be considered desirable in order to assure against slippage of the rail R, sanding means substantially similar to that known and used with railway locomotives may be mounted on the frame of the apparatus 20 adjacent the nip-of the feed wheel means, for supplying sand to the rail R as required.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

lclaim:

1. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising:

frame means including certain frame members movable relative to other frame members for accommodating variation in the height between a rail flange and a rail head;

means supported by said frame means and comprising rotatable members for engaging the base flange and head traction surfaces of a rail and transmitting tractive force to the rail, certain of said rotatable members being carried by said certain frame members for rail height accommodating movement relative to other of said rotatable members;

gripping force means operatively connected to said frame means for moving said rotatable members of said tractive force means from slipping engagement into tightly gripping engagement with a rail passing therebetween and for maintaining such engagement during transmittal of tractive force to the rail so that the force normal to the location of engagement of the rail by said rotatable members is controlled and the frictional transmission of tractive force thereby facilitated; and

motive force means operatively connected to said tractive force means for advancing a rail engaged thereby.

2. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising:

means comprising at least one rail flange wheel and at least one rail head wheel for engaging the base flange and head traction surfaces of a rail and transmitting tractive force to the rail;

frame means supporting said tractive force means and including certain frame members supporting said wheels for rotation about a corresponding plurality of rotational axes, said certain frame members being movable relative to other frame members for accommodating variation in the height between a rail flange and a rail head;

gripping force means operativcly connected to said frame means for applying a force to move said tractive force means into tightly gripping engagement with a rail gripped therebetween so that the force normal to the location of engagement of the rail by said tractive force means is controlled and the frictional transmission of tractive force thereby facilitated; and

motive force means operatively connected to said tractive force means for driving at least one of said wheels in rotation and advancing a rail engaged thereby.

3. Apparatus according to claim 2 wherein said certain members of said frame means include a lever arm member supporting said rail head wheel ofsaid tractive force means for movement therewith about a pivot axis parallel to and spaced from said rotational axes and further wherein said gripping force means acts on said lever arm member and said force is transmitted therethrough to said rail head wheel.

4. Apparatus according to claim 3 wherein said lever arm member has a fulcrum end and a free end and said gripping force means comprises a fluid pressure actuated expansible chamber device interposed between and operativcly connecting said free end and said other members of said frame means.

5. Apparatus according to claim 2 wherein said motive force means comprises at least two normally independent power devices, one of said devices being operatively con nected to said rail head wheel and the other of said devices being operatively connected to said rail flange wheel, so that tractive force is applied through each of said wheels to a rail gripped between said wheels.

6. Apparatus according to claim 5 wherein said motive force means further includes means for coordinating the rotational speeds of said power devices so that the linear surface speeds of said rail gripping wheels are at least substantially identical and slippage of said rail relative to said feed wheel means is avoided.

7. Apparatus according to claim 2 wherein said tractive force comprises two adjacent pairs of superposed rail head and rail flange wheels adapted to engage the flange and traction surfaces of a rail at spaced points along the length thereof, said frame means supports said wheels for rotation about a corresponding plurality of parallel rotational axes, and said motive force means drives at least two of said wheels in rotation.

8. Apparatus according to claim 7 wherein said frame means comprises at least one subframe supported for pivotal movement about an axis parallel to the axes of rotation of said wheels, said subframe mounting two of said wheels for rotation with the respective parallel axes equidistant from and parallel to said axis of subframe support, so that adjustment of said apparatus to rail flexure is facilitated.

9. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising:

frame means including a base, a lever arm mounted for pivotal movement relative to said base about a predetermined first pivotal axis, and first and second subframes respectively mounted on said base and said lever arm for pivotal movement relative thereto about respective predetermined second and third pivotal axes, said first, second and third pivotal axes being parallel;

feed wheel means including at least one rail flange wheel adapted to engage the base flange surface of a rail during handling thereof and supported by said first subframe for rotation about an axis parallel to said pivotal axes and further including at least one rail head wheel adapted to engage the head traction surface of the rail and supported by said second subframe for rotation about an axis parallel to said pivotal axes, said feed wheel means defining a nip between said wheels for receiving a rail to be advaneed;

fluid pressure actuated gripping force means operatively connected to said base and said lever arm for controlling pivotal movement of said lever arm and thereby applying a force urging said wheels together and into tightly 10. Apparatus according to claim 9 and wherein said feed wheel means comprises a pair of rail flange wheels mounted on said first subframe for rotation about axes which are equidistant from said second pivotal axis and a pair of rail head wheels mounted on said second subframe for rotation about axes which are equidistant from said third pivotal axis, whereby flexure of a rail being advanced by said apparatus is accommodated by pivotal movement of said subframes.

Dedication 3,557 ,703.J0hn E. Moorefi'eld, Charlotte, NC. (Charles H. Moorefield, ex-

ecutor of said John E. Moorefield, deceased). RAILWAY RAIL HANDLING APPARATUS. Patent dated Jan. 26, 1970. Dedication filed Dec. 5, 1974, by the assignee, Oke'nwtron Oorpavation. Hereby dedicates to the Public the remaining term of said patent.

[Ofio'cz'al Gazette April I, 1.975.] 

1. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising: frame means including certain frame members movable relative to other frame members for accommodating variation in the height between a rail flange and a rail head; means supported by said frame means and comprising rotatable members for engaging the base flange and head traction surfaces of a rail and transmitting tractive force to the rail, certain of said rotatable members being carried by said certain frame members for rail height accommodating movement relative to other of said rotatable members; gripping force means operatively connected to said frame means for moving said rotatable members of said tractive force means from slipping engagement into tightly gripping engagement with a rail passing therebetween and for maintaining such engagement during transmittal of tractive force to the rail so that the force normal to the location of engagement of the rail by said rotatable members is controlled and the frictional transmission of tractive force thereby facilitated; and motive force means operatively connected to said tractive force means for advancing a rail engaged thereby.
 2. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising: means comprising at least one rail flange wheel and at least one rail head wheel for engaging the base flange and head traction surfaces of a rail and transmitting tractive force to the rail; frame means supporting said tractive force means and including certain frame members supporting said wheels for rotation about a corresponding plurality of rotational axes, said certain frame members being movable relative to other frame members for accommodating variation in the height between a rail flange and a rail head; gripping force means operatively connected to said frame means for applying a force to move said tractive force means into tightly gripping engagement with a rail gripped therebetween so that the force normal to the location of engagement of the rail by said tractive force means is controlled and the frictional transmission of tractive force thereby facilitated; and motive force means operatively connected to said tractive force means for driving at least one of said wheels in rotation and advancing a rail engaged thereby.
 3. Apparatus according to claim 2 wherein said certain members of said frame means include a lever arm member supporting said rail head wheel of said tractive force means for movement therewith about a pivot axis parallel to and spaced from said rotational axes and further wherein said gripping force means acts on said lever arm member and said force is transmitted therethrough to said rail head wheel.
 4. Apparatus according to claim 3 wherein said lever arm member has a fulcrum end and a free end and said gripping force means comprises a fluid pressure actuated expansible chamber device interposed between and operatively connecting said free end and said other members of said frame means.
 5. Apparatus according to claim 2 wherein said motive force means comprises at least two normally independent power devices, one of said devices being operatively connected to said rail head wheel and the other of said devices being operatively connected to said rail flange wheel, so that tractive force is applied through each of said wheels to a rail gripped between said wheels.
 6. Apparatus according to claim 5 wherein said motive force means further includes means for coordinating the rotational speeds of said power devices so that the linear surface speeds of said rail gripping wheels are at least substantially identical and slippage of said rail relative to said feed wheel means is avoided.
 7. Apparatus according to claim 2 wherein said tracTive force comprises two adjacent pairs of superposed rail head and rail flange wheels adapted to engage the flange and traction surfaces of a rail at spaced points along the length thereof, said frame means supports said wheels for rotation about a corresponding plurality of parallel rotational axes, and said motive force means drives at least two of said wheels in rotation.
 8. Apparatus according to claim 7 wherein said frame means comprises at least one subframe supported for pivotal movement about an axis parallel to the axes of rotation of said wheels, said subframe mounting two of said wheels for rotation with the respective parallel axes equidistant from and parallel to said axis of subframe support, so that adjustment of said apparatus to rail flexure is facilitated.
 9. Apparatus for handling lengths of railway rail by advancing the rail longitudinally and comprising: frame means including a base, a lever arm mounted for pivotal movement relative to said base about a predetermined first pivotal axis, and first and second subframes respectively mounted on said base and said lever arm for pivotal movement relative thereto about respective predetermined second and third pivotal axes, said first, second and third pivotal axes being parallel; feed wheel means including at least one rail flange wheel adapted to engage the base flange surface of a rail during handling thereof and supported by said first subframe for rotation about an axis parallel to said pivotal axes and further including at least one rail head wheel adapted to engage the head traction surface of the rail and supported by said second subframe for rotation about an axis parallel to said pivotal axes, said feed wheel means defining a nip between said wheels for receiving a rail to be advanced; fluid pressure actuated gripping force means operatively connected to said base and said lever arm for controlling pivotal movement of said lever arm and thereby applying a force urging said wheels together and into tightly gripping engagement with a rail disposed in said nip therebetween; fluid pressure actuated drive means operatively connected to said feed wheel means for driving said wheels in rotation and thereby applying traction force to a rail gripped therebetween; and fluid pressure means operatively connected to said gripping means and said drive means for supplying fluid pressure thereto and including means for assuring rotation of said wheels in a predetermined correlation.
 10. Apparatus according to claim 9 and wherein said feed wheel means comprises a pair of rail flange wheels mounted on said first subframe for rotation about axes which are equidistant from said second pivotal axis and a pair of rail head wheels mounted on said second subframe for rotation about axes which are equidistant from said third pivotal axis, whereby flexure of a rail being advanced by said apparatus is accommodated by pivotal movement of said subframes. 